Device for protecting the knee joint with a strap

ABSTRACT

The present invention relates to a device for protecting a user&#39;s knee joint, the device being for installing on a sports boot ( 2 ) and being characterized in that it comprises a shell ( 10 ) provided with an inside surface suitable for covering at least in part an anterior portion of the user&#39;s leg, the shell ( 10 ) having a top portion ( 11 ) for situating at knee level and a bottom portion ( 12 ) including connection means suitable for connecting the shell ( 10 ) to the sports boot ( 2 ), the top portion including side cheeks suitable for being put into contact with the knee on either side of the knee, and coming into contact at least with the condyles of the user&#39;s femur, at least one strap ( 3 ) for attaching around a zone of the leg and attachment means for attaching the strap ( 3 ) to the inside surface of the shell ( 10 ).

FIELD OF THE INVENTION

The invention relates to a device for protecting a user's knee joint, which device is for installing on a sports boot. The invention relates to a device for protecting a user's knee joint, which device comprises a shell surrounding part of the anterior and side portions of the tibia and of the knee, the shell being fitted with a strap suitable for controlling rearward movement in translation of the knee relative to the shell. The invention also relates to equipment incorporating such a device, and to a sports boot.

The invention thus finds a particular application in practicing sports or leisure pursuits in which the knee joint is highly stressed, including board sports (including downhill skiing, monoskiing, snow boarding, cross-country skiing) and roller sports (including roller blades and roller skates).

BACKGROUND OF THE INVENTION

The practice of the above-mentioned activities leads every year to numerous conditions associated with the knee joint, which might be nothing more than strains, or which might be accompanied by torn ligaments.

As a general rule, at least in downhill skiing, unacceptable stresses on the knee joint are avoided by boot bindings that are suitable for releasing the boot if the torque exerted on the binding exceeds a predetermined value. However determining this trigger value for releasing the binding is itself problematic.

Document US-A1-4 136 404 describes a device capable of acting in addition to the action of a ski binding and suitable for attaching to a ski boot. However the system disclosed is complex in structure and is clearly uncomfortable: the skier's lower limb is held on either side of the knee up to the thigh in a leg-brace that is hinged at knee level. Its co-operation with the knee joint for the purpose of protecting it is also not very effective.

WO 2007/061379 describes equipment that serves only to protect an ice hockey goalkeeper but that does not include a rigid shell and in which a connection strap 311 is attached around the leg in the knee joint zone. That device therefore does not enable forces applied to the device at knee level to be transferred to the boot, and to do so without impeding frontal flexion movements at knee level.

There therefore exists a need for devices for protecting the knee joint that mitigate at least in part the drawbacks of previously known techniques.

The invention seeks to limit the risks of knee injuries, in particular sprains and torn ligaments associated with excessive relative axial rotation of the tibia or femur and/or excessive shear in the XY plane. The invention seeks to provide a protection device that does not hinder the skier under normal skiing conditions, in particular in terms of frontal flexion at the knee.

Movements in rotation and in translation between the tibia and the femur are measured relative to three axes at the knee. For this purpose, if a local frame of reference is defined that is tied to the top end of the tibia: the substantially horizontal XY plane is the plane of the tibial plateau; with the Z axis being the longitudinal axis of the tibia.

In this frame of reference, the following movements in rotation and in translation can take place:

-   -   relative axial rotation of the tibia about Z at the knee,         correspond to the angle between two transverse vectors of the         tibia and of the femur, one at the tibial plateau and the other         between the two condyles of the femur, this rotation being         projected onto the tibial plateau (XY plane); and     -   rotation in sideways flexing corresponding to the angle between         the two transverse vectors of the tibia and the femur, but in         the YZ plane, also referred to as valgus-varus; and     -   rotation in frontal flexing corresponding to the angle between         two longitudinal vectors of the tibia and of the femur in the XZ         plane; and     -   shear of the knee corresponding to movements in translation         between the tibia and the femur along the three axes X, Y, and         Z, and in particular shear towards the front of the femur along         the X axis.

The natural mobility of the knee depends on its frontal flexion angle in the XZ plane in axial rotation about Z. Although the knee does not allow the tibia to rotate axially relative to the femur while the knee is in full extension, the amplitude of the external or internal axial rotation of the tibia that is allowed by the knee increases with increasing frontal flexion angle. Thus, with a frontal flexion angle between the femur and the tibia of 90°, the internal axial rotation of the tibia is about 30°, correspondingly bringing the toe inwards, in combination with the adduction or abduction movement of the foot. The external axial rotation of the tibia is about 40° in external rotation. Although the locking of the ankle by the ski boot limits very strongly this amplitude of axial rotation of the tibia, it can still reach 20° in internal rotation and 25° in external rotation, giving a total amplitude of 45°.

The object of the present invention is to provide a device seeking essentially or mainly to limit shear in the tibial plane, in particular forward shear of the femur along the X axis, and axial and sideways relative rotations between the femur and the tibia, without interfering with frontal flexion at the knee, and in particular without having recourse to a pivot connection at the knee and/or without having recourse to a direct connection around the thigh.

Another object of the present invention is to provide a device that is simple to fabricate and to install on the lower limb and that is suitable for being useful to a skier regardless of the pair of skis in use.

In the present invention, the device essentially comprises merely a rigid shell provided with side cheeks in its top portion, without any connection with the thigh and with means for connecting the shell to the cuff that enable rotation of the shell and of the cuff about an axis substantially parallel to the longitudinal Z axis to be limited in controlled manner.

SUMMARY OF THE INVENTION

To do this, the present invention provides a device for protecting the knee joint of a user, the device being for installing on a sports boot, and being characterized in that it comprises:

-   -   a rigid shell having an inside surface suitable for covering at         least in part an anterior portion of the user's leg, the shell         having a top portion for being situated level with the knee and         a bottom portion including connection means suitable for         connecting the shell to the sports boot, the top portion         including side cheeks suitable for extending over side faces of         the knee and suitable for being put into contact with the side         faces of the knee at least facing the condyles of the user's         femur;     -   at least a first strap for attaching around a zone of the top         portion of the leg below the knee, preferably at the top portion         of the calf; and     -   attachment means for attaching the strap to the surface of the         shell;

said first strap, on its own or in combination with said attachment means, being suitable for surrounding the leg entirely and for being in contact with the leg over the entire periphery of its section.

The function of this device is to transmit force between the top of the lower limb and the boot so as to off-load the knee joint. Pressure of the shell against the condyles of the femur, together with a connection of the shell to the boot both contribute to this effect, by diverting away from the knee joint mechanical stresses that it cannot withstand without injury. In this context, said first strap and said connection means, by co-operating with the shell and the tibia, enable the top portion of the shell to be applied effectively against the knee, even during movements performed by the user.

More precisely, the essential main function of the rigid shell is to support the cheeks and to transfer the thrust forces of the knee against the cheeks down to the boot and thus down to the binding holding the boot on the ski, since it is the binding that determines the acceptable level of force, with the binding releasing the boot beyond a certain threshold. The secondary function of the shell is to protect the front of the tibia against possible impacts. The surfaces of the cheeks thus perform an essential role because the transfer of force is maximized when the sides of the knee are pressing against the cheeks if the thrust surface area of the cheek against the side of the knee is optimized.

Consequently, the thigh is held relative to the boot by using simple cheeks, possibly acting via interposed spacers as described below, that press against the soft tissue covering the condyles and/or the distal epiphyses of the femur in association with a rigid tibia-protecting shell that is limited in the movements it can perform relative to the ski boot. This limitation very greatly reduces any risk of pathological movements in axial or sideways rotation between the tibia and the femur at the knee, and/or limits risks of shear, in particular forward shear of the femur along the axis X.

Because the rigid shell of the present invention is fastened to the boot and because it includes rigid side cheeks in its top portion, it thus presents more generally the function of protecting the knee joint by controlling relative movements of the knee in forward translation and in rotation relative to the shell.

The main function of the said first strap is to control rearward movement in translation of the knee relative to said shell during movements and/or deformation of muscle masses and/or soft tissue during flexion movements of the lower limb.

In particular, the way in which the first strap is connected around the top portion of the leg, below the knee and not at the level of the knee, provides good control over rearward movement in translation of the knee relative to the shell, and thus enables the knee to be held in position facing the side cheeks so that the device can perform its protective function without impeding movements of the lower limb, because said strap is attached below the knee.

The characteristic whereby said first strap follows the outline of the leg, thus serves to optimize the function of said first strap and the connection of the shell to the leg without causing the shell to move in rotation relative to the boot in the event of movement in rotation at the knee.

The advantages of this embodiment are explained below with reference to FIGS. 1A and 1B. An embodiment of the invention is shown in FIG. 1A. This embodiment is advantageous compared with the embodiment shown in FIG. 1B where the strap 3′ has two independent strands with fastener points arranged on the side edges 10 d of the shell, the strap 3′ being in contact with only the posterior portion of the leg.

During tests that have been performed, it has been found that, under certain circumstances, in the embodiment of FIG. 1B, the shell can be subjected to forward movement in translation along the axis X relative to the knee, and that on the contrary the knee may be subjected to rearward movement in translation relative to the shell along the axis X, i.e. that the knee can escape from the shell and as a result the device no longer performs its protective function.

This occurs in particular during flexion movements of the limb and during a movement of the knee in rotation relative to the shell, in particular as from a flexion angle of 35° of the femur relative to the tibia. These movements cause the condyles of the femur to move relative to the shell, which can have the consequence of causing the knee to perform relative rearward movement in translation, the knee no longer being protected by the cheeks and thus giving rise to situations in which there is a risk of injury.

This relative movement in translation of the knee during said flexion movements of the lower limb is the result of movements of muscles and of deformations of soft tissue that change the shape of the outline of the constant-perimeter section of the leg, and in particular leads to a change in the volume of the leg in its posterior portion, it being possible for the soft tissue over said condyles to present a thickness of about 1 centimeter (cm).

In the embodiment of FIG. 1B, the fact that the strap covers only the posterior portion of the leg means that a reduction in the volume of the posterior portion of the leg leads to the pressure of the strap being relaxed, thus enabling the knee to move in translation rearwards relative to the shell. Said first strap no longer acts in satisfactory manner to perform its function of preventing the knee from moving rearwards in translation relative to the shell.

In contrast, in the embodiment of the invention shown in FIG. 1A, because the strap 3 covers the entire periphery of the leg, which periphery continues to have a constant perimeter, any change to the volume of the leg has no effect on contact between the strap and the leg, and said means for connecting the strap to the inside surface of the shell prevent the knee from moving rearwards relative to the shell, in spite of movements of the condyles and/or flattening of the soft tissue.

This embodiment of the invention thus makes it possible in simple and astute manner to restrict rearward movement in translation of the knee relative to the shell and to conserve substantially constant tension in the strap that is in contact with the leg during a flexion movement of the lower limb, and in spite of the overall change in the shape of the section of the leg and in spite of the movements and deformations of the muscles and of the soft tissue.

Furthermore, in the embodiment of FIG. 1B, after the strap has been tightened on the soft tissue, the strap induces pressure by pressing only against the posterior portion of the leg, which pressure varies depending on the angular position of the femur relative to the tibia, with pressure increasing or decreasing depending on the position occupied by the skier while tightening said strap on the leg. If the skier tightens the strap while in the relaxed or standing position, then the pressure of the strap decreases as from flexion with an angle of approximately 35° between the tibia and the femur. In contrast, while in a sitting or flexed position, the pressure on the leg increases considerably when the skier stands up and gives rise to a considerable impediment as a result of shear applied to the soft tissue at the top of the calf.

In contrast, in the embodiment of FIG. 1A, and of new claim 1, the strap provides almost constant pressure on the soft tissue and therefore does not cause pressure on the posterior portion of the leg to change and does not run any risk of applying shear to the soft tissue at the top of the calf depending on angular position, while also maintaining a constant position for the knee relative to the shell. Finally, it should be observed that in the embodiment of the invention and in FIG. 1A, said connection means occupy the space between the shell and the front portion of the leg, thereby enabling the strap to go all around the leg under all circumstances. This space between the front portion of the leg and the shell is necessary because the shell is pressed against the cuff of the boot and against the knee via spacers.

Said connection means serve to occupy the space between the inside surface of the shell and the front portion of the leg, thus enabling said first strap—once tightened around the leg—to go all around the leg without coming into contact with said shell, and being capable of remaining in contact with the entire perimeter of the leg during the various movements and/or deformations of the muscle mass and of the soft tissue in the portion of the leg with which said first strap is in contact.

Preferably, said connection means are flexible, being made of non-stretch material, and said first strap is a flexible strip of non-stretch material, in particular of textile material. Said flexible connection means make it possible during an impact to prevent the tibia from coming into contact with a rigid part that might lead to injury.

More particularly, the attachment means are fastened to at least one attachment zone of the inside surface of the shell, said attachment means being arranged symmetrically about the middle of the width section of the shell, said shell preferably having a shape that is symmetrical about a longitudinal midplane.

Preferably, in horizontal section, said shell presents a shape of rounded profile, with its convex bulging face facing towards the front so that its concave shape faces towards the rear covering the front and parts of the side faces of the knee and/or of the tibia, and extending over a portion only of the sides of the tibia, and at its bottom end, extending over a portion of the sides of the cuff. The shell may extend over a height of 25 cm to 55 cm and preferably over a height of 30 cm to 50 cm, in practice depending on the size of the skier, and said connection means enable the shell to be spaced apart from the front portion of the tibia by 3 millimeters (mm) to 50 mm.

More particularly, the connection means include at least one intermediate piece having at least a first portion that is fastened to the inside surface of the shell and having at least one second portion that is fastened to the portion of the first strap.

Still more particularly, the attachment means include at least a single intermediate piece having its central portion fastened to a single attachment zone of the inside surface of the shell, substantially in the middle of the section of the shell, with its two side portions arranged on either side of said central portion substantially symmetrically about said connection zone being fastened to the portion of the first strap that is suitable for coming into contact with the front portion of the tibia.

Still more particularly, the intermediate piece is connected to the inside surface of the shell at a height up the shell such that the strap comes to press against a top portion of the user's calf facing said attachment zone of said intermediate piece with said inside surface of the shell.

Preferably, said intermediate connection piece comprises a piece of flexible material, preferably constituted from a flexible strip of non-stretch material.

Still more particularly, said first strap includes at least a first portion situated facing the inside surface of the shell and suitable for coming into contact against the anterior portion of the leg, and at least one second portion extending beyond the first portion, the width of the first portion being greater than the width of the second portion.

It has been found that a greater width of strap on the front face of the leg can improve comfort and reduce local stresses by spreading forces over a larger area, since the front face of the leg has a smaller thickness of soft tissue and thus the pressure at the surface of the soft tissue increases.

Advantageously, at least a portion of the face of the first strap that is to be exposed to contact with the leg includes a covering of damping material, preferably of a soft material of cellular material type or of gel type.

More particularly, said first strap has two strands that are distinct or in continuity with each other at a first end of each strand, the two strands being suitable for extending at least over two respective sides of the leg and comprising said first ends that are fastened to said attachment means, the second free ends of the two strands being suitable for joining together over the posterior portion of the leg.

Advantageously, said first strap includes a buckle frame of flexible material at the free end of one of the strands and/or a Velcro type self-adhesive system configured to secure the free end of the other strand on the posterior portion of the leg, said frame preferably being an orifice incorporated in the end of a first strand that is greater in width than the end of the second strand, which second strand is suitable for passing through said frame.

Preferably, the device includes spacers pressed against the inside faces of said cheeks and presenting bearing surfaces of ergonomic shapes suitable for fitting closely in part at least to the shapes of the sides of the knee at the level of the condyles so as to block forward movement in translation of the knee relative to the shell and so as to block movement in rotation of the knee relative to the shell, without hindering flexion movements of the lower limb, preferably spacers molded to have embossed shapes complementary to the shapes of the side faces of the knee at the level of the condyles. The essential functions of said spacers are firstly to block movement in rotation of the femur relative to the tibia and thus relative to the shell, about the Z axis and secondly to block forward movement in translation of the knee relative to the shell. The function of said first strap is to block rearward movement of the knee relative to said shell. The spacers do not serve to block rearward movement in translation of the knee relative to the shell because they are configured to avoid impeding flexion movements of the lower limb.

Preferably, the spacers are molded to have shapes with surfaces that are complementary to the surfaces of the side faces of the knee as observed at the level of the condyles between at least two flexion positions.

This characteristic makes it possible to adapt a common shell to condyles having a variety of dimensions by interposing a variety of spacers. A common molded shell can thus be used for different sizes of device and also for making devices that are personalized. Under such circumstances, only the spacers need to be modified in order to obtain a variety of sizes or in order to obtain a personalized device.

The inside surfaces of the spacers may preferably be made to measure so as to match the shape of the lower limb of a particular skier without hindering the flexion/extension movements of the knee.

Thus, the ergonomic spacers match in part the shape of the morphology of the sides of the knee without hindering frontal flexion of the knee. The area defined by the outline of a spacer thus corresponds to the area defined by the outline of the cheek as described below and thus presents a value of at least 50 square centimeters (cm²), and preferably of at least 100 cm².

Advantageously, these ergonomic spacers may present a surface that is the result of melding the surfaces observed at the condyles of the skier for at least two preferred angular positions of the skier's lower limbs, and in particular with an angle α between the vertical and the femur lying in the range 70° to 135°.

This personalization characteristic enables the device to be particularly agreeable to use in all skiing positions. Furthermore, this personalization of the protection device of the invention is most advantageous insofar as it serves to provide a very secure connection between the side cheeks and the knee. This avoids any penalizing clearance being present at this point of the device, where such clearance would involve the femur being free to turn through an angle relative to the boot that is greater than the maximum angle determined by the device of the invention.

Advantageously, said cheeks and/or spacers include linings of flexible material for coming into contact with the sides of the knee of the skier (S). Still more particularly, each of said spacers comprises a rigid support covered in a lining of flexible material for coming into contact with the skier's knee, i.e. the portion that is to press against a side of the knee. The linings are arranged on the inside faces of the cheeks, or preferably on the inside faces of the spacers, when spacers are used.

This characteristic increases skier comfort without degrading the effectiveness of the invention in terms of movements in rotation about the Z axis.

The lining may be made of a flexible material of the cellular material type (foam etc.), or of the gel type (silicone, etc.). The lining is thus advantageously made from at least one elastomer or plastics material of the ethylene vinyl acetate (EVA) type or of some other type that is optionally thermoformable and that presents thickness and density that are sufficient to provide comfort during movements of the lower limb while skiing. More particularly, the material may be a silicone gel in the form of a plate having thickness lying in the range 1 millimeter (mm) to 10 mm, and preferably in the range 2 mm to 5 mm.

The shell and the spacers are advantageously made of a rigid material that may be inorganic or organic, and it may be in a single piece or it may be in composite form, using materials selected from the following: magnesium, aluminum, titanium, metal alloys, polymers that may optionally be filled and that may optionally be reinforced, and resins that may optionally be composite, that may optionally be filled, and that may optionally be reinforced.

Advantageously, the composite is constituted by a matrix based on a thermosetting type resin such as epoxy, polyester, etc., or on a thermoplastic resin of the polyamide (PA) type or of the polycarbonate (PC) type or of some other type, together with at least one reinforcing material. The reinforcing material may be based on carbon fibers and/or on glass fibers and/or aramid fibers, e.g. on Kevlar® (trademark of the supplier of Dupont de Nemours) and/or on poly p-phenylene-2,6-benzobisoxazole (PBO)® (trademark of the supplier Toyobo Japan), and/or on PIPD M5 from the supplier Dupont de Nemours, and/or on ultra high molecular weight polyethylene (UHMWPE) DYNEEMA (trademark of the supplier DSM Holland). The reinforcing content in the composite lies in the range 0% to 70%. The reinforcement may be woven or knitted or braided, and it may be of the two-dimensional, or three-dimensional, or uni-dimensional type, or it may be constituted by cut fibers. Organic or inorganic fillers may be added to the matrix depending on the desired specifications. It is possible for the polymer material of the matrix and for the reinforcing fibers to contain carbon nanotubes in order to improve their mechanical characteristics. These materials generally serve to provide the shell and the spacers with good stiffness while also being light in weight and comfortable.

More particularly, the shell is made of a composite material constituted by carbon fibers, possibly mixed with fibers of other types, and impregnated in a polymer resin, preferably an epoxy resin.

In an advantageous embodiment, the rigid support for the spacers is made of a balsa wood type material. This material presents the characteristics of high resistance to compression, in particular in the range 1 megapascal (MPa) to 30 MPa, and more particularly in the range 5 MPa to 25 MPa for relatively low densities respectively of 50 kilograms per cubic meter (kg/m³) to 300 kg/m³, and more 100 kg/m³ to 250 kg/m³.

More particularly, balsa is used under the trademark Baltek® SB 100 or 150 as sold by the supplier Alkan Baltec Corporation (USA).

At least on a face of the lining that comes into contact with the lower limb, it is possible to apply a film or a fabric of the spandex or stretch type having a thickness of at least 10 micrometers (μm), the film or fabric being attached by adhesive to said surface in order to match the shape of the spacer.

The material of the film or fabric may present a low coefficient of friction. By way of example, the material may be made from polytetrafluoroethylene (PTFE) (e.g. of trademark Teflon in the name of Dupont de Nemours, USA). The thickness of the film or of the fabric is selected depending on the desired mechanical characteristics.

When the cheeks or the spacers include a flexible lining over the portion that is to press against the sides of the knee, said connection means need not authorize any degree of freedom for the shell to move relative to the boot about an axis Z substantially parallel to the axis of the cuff of the boot, since the condyles of the femur are held by the spacers positioned in the cheeks and the spacers allow for a small amount of relative axial movement in rotation between the femur and the tibia because the soft tissues between the condyles and the spacers deform when performing a movement in rotation. The angular sector is thus limited sufficiently by the shape and the clearance of the spacer in contact with the soft tissue over the condyles of the femur.

In general, the capacity of the device for adjustment and adaptation by using spacers enables the device to be adapted to the variability of skiers: age, sex, physical condition, muscle tone, contraction levels, etc. . . . The expected levels of stress conditions are also corresponding parameters for adjusting the device: shear, lateral section, speeds, skier position, vertical acceleration, prestress between the device and the knee, etc.

More particularly, between the side cheeks, and where appropriate between the spacers, the device also has a cushion 30 c for pressing against the user's kneecap, said cushion preferably being made of a cellular material having density lying in the range 30 kg/m³ to 900 kg/m³.

More particularly, each of said spacers and said cheeks presents an outline substantially with the shape of a portion of an ellipse over the top portion and the rear portion of said outline of the cheek, the major axis X1 of the ellipse sloping at an angle α lying in the range 45° to 135°, and preferably lying in the range 70° to 110°, relative to the main longitudinal Z axis of the shell and/or relative to the shell in section in a longitudinal vertical midplane of the shell.

The preferred use of cheeks having an elliptical outline is particularly suitable for providing sideways support to the flanks of the thigh, with the orientation of the cheeks enabling the skier's femur to be supported correctly in the skiing position without hindering the skier.

Still more particularly, the major axis of the ellipse is at least 5 cm long, and preferably of a length lying in the range 6 cm to 15 cm, in particular in the range 8 cm to 11 cm and the minor radius of the ellipse is at least 2 cm long, and more particularly lies in the range 3 cm to 10 cm.

Still more particularly, the major axis of the ellipse is situated at 2 cm to 5 cm from the top end of the shell, and the center of the ellipse is situated at 5 cm to 10 cm from the rectilinear section of the front face of the shell in section on a longitudinal midplane of the shell.

Such dimensions for the ellipse and such an angle of inclination for the major axis of the ellipse lying in the range 70° to 110° enable the relationship between the cheeks and the end of the bottom femoral epiphysis to be maintained in spite of the movement of the condyles during flexion/extension movements of the knee. This angle of inclination also corresponds to an intermediate angle of inclination between the positions of the thigh in movement or at rest. More particularly, the cheeks present surface areas suitable for covering the entire surface area of both sides of the knees, each cheek preferably having an area of at least 50 cm², and more preferably of at least 100 cm².

Such a size for the cheeks makes it possible to ensure good coverage of the distal epiphysis of the femur and of the femoral condyle, while ensuring that the device of the invention does not hinder the skier.

The surface of each cheek corresponds substantially to the surface of the top side portion of the shell situated above the bottom tangent X2 of the ellipse parallel to the major axis X1 of the ellipse and situated behind an axis parallel to the minor axis Z1 of the ellipse (and thus perpendicular to the major axis of the ellipse) situated about halfway along the major radius (R) of the ellipse starting from the rectilinear section of the front face of the shell in a vertical longitudinal midplane of the shell.

More particularly, the center of the ellipse is located substantially facing the condyle to within ±20 mm depending on the flexing at the knee. The bottom tangent to the ellipse parallel to the major axis of the ellipse is situated substantially facing the tibial plane when the major axis of the ellipse is at substantially 90° to said longitudinal axis of the shell parallel to the rectilinear section of the front face of the shell in section on a longitudinal midplane of the shell.

More particularly, said boot includes a cuff and said connection means are suitable for securing the bottom portion of the shell to the cuff portion of the boot covered by the bottom portion of the shell in such a manner as to limit rotation of the shell relative to the boot about an axis that is substantially parallel to the axis ZZ′ of the shell and/or of the cuff. This embodiment of the connection means also serves to optimize the transfer of forces to the boot, because of the way the shell is connected on said boot.

More particularly, said connection means comprise first connection means suitable for being fastened to the cuff of the boot and second connection means complementary to the first connection means of the cuff for securing with the cuff of the boot, said connection means preferably comprising at least one second strap and/or at least one third strap fastened to or suitable for being fastened to said shell and suitable for being fastened to said cuff.

The connection between the low portion of the shell and the cuff of the boot provided by associating the first and second connection means provides a connection giving the shell at least one degree of freedom to move in rotation relative to the boot about an axis substantially parallel to the axis of the cuff of the boot, the attachment means being such that this movement in rotation of the shell relative to the boot is limited to a predetermined angular sector, preferably of less than 14°.

Such angular limitation makes it possible in particular to provide increased protection to the tibia and the knee joint while leaving latitude of movement that is appreciable in certain skiing situations. An angular limitation of 14° corresponds on average to the acceptable angular amplitude of axial rotation about the Z axis between the tibia and the femur of less than 45°.

Said first and second connection means preferably prevent the shell 10 from moving in rotation relative to the boot 2 about an axis substantially parallel to the axis ZZ′ of the shell or of the cuff (21) of the boot 2.

This embodiment of said second and/or third straps makes use either of the stretchability of the second strap adapted as a function of the desired limitation on movement in rotation, or on a particular adjustment of the tightening of the second strap and/or third strap which should then be inextensible, so as to allow a limited amount of movement in rotation of the shell relative to the boot. Such a particular adjustment of the clamping of the second strap and/or third strap allowing a limited amount of movement in rotation over a predetermined angular sector is achieved by means of a mechanical element enabling the strap to be lengthened or shortened or enabling the second strap and/or the third strap to be maintained at a predetermined length. This type of device makes it easier to establish the connection between the shell and the cuff.

Thus, in a particular embodiment, the first and second connection means comprise two straps, a second strap and a third strap, each of which has one end fastened to the cuff and its other end fastened to the shell, with the extent of the straps limiting rotation in each of two opposite directions of rotation, and preferably preventing any such rotation.

The use of two straps, the second strap and the third strap, makes it possible to adjust the movement in rotation of the shell in both directions of rotation and thus to limit this movement in both directions of rotation.

In a variant, the first connection means comprise at least one guide part for installing on the cuff of the boot, said guide part being suitable for co-operating with the second connection means of the shell that are complementary to said guide part so as to limit movement in rotation to the predetermined angular sector.

This embodiment may involve installing at least one particular element on each boot for enabling the shell connection means to operate by accurately controlling the behavior of the shell relative to the boot. It is envisaged herein that these first connection means installed on the boot are elements that are present on the boot by default, such as a fastener or other element relative to which the shell takes up its position in order to have its movement in rotation limited.

The invention also provides equipment for board sports or for roller sports including a sports boot and a protection device.

More particularly, the present invention provides sports equipment comprising a sports boot 2 including said first connection means and a protection device of the invention including said second connection means.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the present invention appear from the following description made with reference to the accompanying drawings which show embodiments having no limiting character.

In the figures:

FIGS. 1A and 1B show the principle of attaching the first strap 3 on an attachment piece situated on the inside face substantially in the middle of the shell 10 of a device of the invention (FIG. 1A) in comparison with an attachment of a strap 3′ fastened to the side edges 10 d of a shell that is not in accordance with the present invention (FIG. 1B);

FIGS. 2 and 3 show an attachment piece and a first strap in perspective without the leg (FIG. 2) and around the top portion of the calf (FIG. 3);

FIGS. 4A to 4C are views of the shell, in front face view (FIG. 4A), in profile view (FIG. 4B), and in plan view (FIG. 4C);

FIG. 4C shows a shell of substantially circular horizontal section, the side cheeks 11 a and 11 b also being slightly curved in the opposite direction to the two sides;

FIG. 5A shows the shell fitted with first connection means comprising second straps 13 a-1, 13 a-2 on a variant embodiment;

FIG. 5B shows the boot fitted with complementary second connection means comprising third straps fastened to a hook 23 at the rear of the cuff 21;

FIG. 5C shows an embodiment for linking said first and second complementary connection means of FIGS. 5A and 5B;

FIGS. 6A and 6B show variants in which said first and second complementary connection means comprise a single pair of second or third straps 13 a or 13 b connecting a fastener piece 23 to the rear of the cuff, and side orifices O in the bottom portion 12 of the shell;

FIG. 7 shows a device of the invention having spacers 30 a, 30 b and a central cushion 30 c;

FIGS. 8A and 8B show the spacers 30 a, 30 b constituted by a flexible lining 30-1 over a rigid support 30-2;

FIGS. 9A and 9B show a third embodiment of said connection means; and

FIG. 10 shows different angles alpha for frontal flexion of the femur and an inclination of 70° for the major axis of the ellipse of the cheeks 11 a, 11 b.

DETAILED DESCRIPTION OF AN EMBODIMENT

Unless otherwise specified in the present description, the term “leg” is used to designate the portion of a user's lower limb that is fitted with the device of the invention in register with the tibia bone. It is thus a zone extending under the knee towards the foot. In its portion situated above the knee, the bony structure of the lower limb comprises the femur, i.e. the thigh bone. At the knee, there is a kneecap. The tibia and the fibula are the bones of the leg. At its top end, the tibia has a joint via tibial plateaus to the bottom portion of the femur (femoral condyles).

FIG. 10 is a diagram of the invention. This figure shows the bottom of the body of a skier S. The skier S has a ski boot 2, which is fastened to a ski 1 by means of a binding 1 a. The boot 2 has a footwear portion surmounted by a cuff 21. The foot P, the tibia T, and the femur F of the skier S can be seen. The femur F has condyles CF at its distal end. These condyles CF occupy a plurality of intermediate positions between two extreme positions that are shown in FIG. 10, as a function of the flexion position of the skier S.

In FIGS. 1 to 7, the skier S is wearing a device of the invention. The device comprises a rigid shell 10 having a high portion 11 and a low portion 12. The low portion 12 covers the top portion of the cuff 21 and includes connection means for securing the shell 10 with the cuff 21 of the boot 2. The high portion of the shell 10 presents two side cheeks 11 a and 11 b that cover the side faces of the knee overlying the condyles CF of the femur F on either side of the leg of the skier S, this covering being provided by the side cheeks regardless of the flexion position of the skier S.

The shell is made of a material comprising carbon fibers, optionally mixed with other types of fiber in particular fibers of flax or of polymer, e.g. an aramid, said fibers being impregnated with an epoxy resin, the fiber content lying in the range 45% to 65%, and preferably in the range 50% to 60%. The shell may be constituted by a monolithic structure of said carbon fiber-based composite material or by a sandwich structure, i.e. made up of two layers of said carbon fiber-based composite material constituting two outer skins on either side of a honeycomb core made of aluminum or of a cellular foam under the trademark Rohacell® or Airex®.

In general, the present invention serves to protect the knee by transferring at least some of the mechanical stresses induced on the condyles CF of the femur towards the base of the leg, and in particular towards the boot 2 worn by the user. In order to transit the stresses that the knee joint would not be capable of absorbing without lesions, the device of the invention includes a shell 10 that is made in sufficiently rigid manner. The shell 10 has a long dimension oriented in the Z direction substantially from the knee (high portion 11) to the cuff 21 of the boot 2 (low portion 12). In FIG. 5A, the height H of the shell lies in the range 25 cm to 55 cm, and more particularly in the range 30 cm to 50 cm, depending on the size of the skier. The shell 10 advantageously presents a sideways dimension that is sufficiently great to enable the shell 10 to oppose sufficient resistance to twisting about the direction of the tibia T. The distance D between the two cheeks should lie in particular in the range 8 cm to 20 cm. The portion of the shell between the cheeks presents a rounded horizontal section with its concave side facing towards the leg, in particular a section that is substantially circular in part in the front region with a radius lying in the range 2 cm to 15 cm, and more particularly with a radius lying in the range 3 cm to 8 cm.

In order to enable the device to be always properly in contact with the sides of the knee at the condyles CF, the device includes at least a first strap 3 that is visible in FIGS. 2 and 3 and suitable for surrounding the leg, and that is also attached to the shell 10. Advantageously, the first strap 3 is configured to bear against a high portion of the leg, i.e. a zone at the top end of the calf. More precisely, the first strap 3 is advantageously positioned around the leg immediately below the knee joint.

Any material may be suitable for the first strap 3 and in particular it is possible to use polymer textile materials that are non-stretch or that present little elastic lengthening so as to produce little variation in the length of the strap 3 while it is being stressed. By way of example, the first strap 3 may be in the form of a single strip or of a plurality of strips. In all circumstances, the first strap 3 may present a total width lying in the range 2 cm to 6 cm.

FIGS. 2 and 3 show in greater detail a first embodiment of the first strap 3 and how it is attached to the shell 10. In the invention, the first strap 3 is attached to the shell 10 via the inside surface 4 of the shell 10. The term “inside surface” 10 b is used to mean the surface of the shell 10 that is situated directly facing the leg, being opposite from the outside surface 10 a which faces towards the outside.

Because the first strap 3 is attached in this way, co-operation between the shell 10 and the user's leg is particularly intimate and while moving the user avoids any changes of contact between the sides of the knee at the condyles CF and the side cheeks 11 a, 11 b.

In the example shown in FIGS. 2 and 3, the first strap 3 is constituted by two strands 3 a, 3 b that are integral with a strand 3 a on one side of the leg and a strand 3 b on the other side of the leg. The two strands advantageously join together via a portion 3 c of the first strap facing the anterior or front portion of the leg facing the tibia and facing the inside surface 10 b of the shell 10 substantially in the middle of the section of the shell 10.

The attachment of the first strap 3 to the shell 10 as constituted in this way takes place in the example shown via attachment means comprising an intermediate piece 4 secured firstly to the first strap 3 and secondly to the inside surface 10 b of the shell 10. It is secured to the inside surface 10 b via an attachment zone 10 c of said inside surface 10 b. This attachment zone 10 c is advantageously located substantially in the middle of the width of the shell 10 so as to have a first strap system 3 that is substantially symmetrical about a vertical plane containing the tibia. The intermediate piece 4 is also fastened to the first strap 3. In the example shown, this fastening is balanced by making use of two fastening zones, respectively referenced 4 a and 4 b that, after fastening and positioning on the leg, are arranged at equal distances from the attachment zone 10 c. Thus, the portion 3 c of the first strap 3 extends between the fastening zones 4 a and 4 b.

An advantageous effect of the intermediate piece 4 is that it ensures optimum adjustment of the 3 mm to 50 mm spacing between the zone of the leg under consideration for application of the strap 3 and the inside surface 10 b of the shell. Making use of the invention thus gives the possibility of adjusting the relative position of the device and of the user's leg in a front/back position.

More specifically, in FIGS. 2 and 3, said intermediate piece 4 is constituted by a flexible strip of non-stretch material, preferably the same non-stretch flexible material as said first strap, said flexible intermediate piece 4 forms a loop because:

-   -   a central portion 4 c of said loop is fastened on an attachment         zone 10 c of the inside surface 10 b of the shell, said zone 10         c preferably being arranged in the middle and symmetrically         about the middle of the section of the shell; and     -   two side portions 4 d on either side of the central portion 4 c,         presenting ends 4 a, 4 b of said intermediate piece on either         side of said loop that are fastened on a central portion 3 c of         said first strap for coming into contact with the front portion         of the tibia, the ends 4 a and 4 b being arranged symmetrically         about said first portion 4 c in the middle of the section of the         shell.

In FIGS. 2 and 3, although the attachment piece 4 is constituted by a flexible strip, it is shown as having side elements 4 d of the flexible strip in a position as far away as possible from the shell, so it is tensioned.

The central portion 3 c of the first strap is extended on either side by two strands given respective references 3 a and 3 b. The end 3 d-1 of one of the strands 3 a presents a buckle frame 5 through which the end 3 d-2 of the second strand 3 b can pass. The frame 5 is preferably made of flexible material so as to present an orifice incorporated at the free end 3 d-1 of one of the strands 3 a that is of width greater than the end 3 d-2 of the second strand 3 b suitable for passing through said frame and including a self-adhesive or self-gripping element of Velcro type configured to secure the free end 3 d-2 of the other strand 3 b to the end 3 d-1 of a first strand 3 a on the posterior portion of the leg.

It has been found that a frame 5 of rigid material can lead to inflammation of soft tissue. The advantage of a frame made of flexible material such as a textile is that it complies with changes to the shape of soft tissue. Furthermore, having a portion of the strap with a greater width enables a textile frame to be cut out from one of its ends and thus enables the other end of the strap to be attached by passing through the opening in said frame. The frame at one of the ends of the strap may be made of textile material and may form an integral part of said strap.

The intermediate piece 4 may be fastened to the inside surface 10 b of the shell 10 in various ways, and in particular by stitching or by riveting or by screw fastening. The intermediate piece 4 may likewise be fastened to the first strap 3 in the fastening zones 4 a and 4 b by any means. When using an intermediate piece 4 made of flexible material, of the textile material type, a plurality of stitches may be used for attaching it to the strap 3.

In a variant (not shown), the intermediate part 4 includes, in the same manner, two fastening zones 4 a and 4 b for fastening to the strap 3, but the strap is made as two distinct strands 3 a and 3 b, i.e. there is no strap portion 3 c between the fastening zones 4 a and 4 b, but rather a link portion of the intermediate piece 4 between the zones 4 a and 4 b. In this way, the first strap 3 in combination with the portion interconnecting the zones 4 a and 4 b of the attachment piece may be applied in continuous manner against the entire periphery of the leg in question.

A variant that is not shown consists in providing for each of the strands 3 a and 3 b to be fastened to the shell 10 via a distinct attachment zone, but with the strands 3 a and 3 b being attached together between these attachment zones. Thus this reproduces a single piece strap solution that is continuously in contact around the leg, but that has two attachment zones with the shell.

In a configuration that is not shown, at least one of the strands of the first strap 3 is such that a fraction of its length has a first width dimension and a second fraction of its length has a second width dimension that is narrower. In particular, the narrower zone may correspond to the distal portion for assembling with the other strap strands. For example, the strap may be of varying width. On the anterior portion of the leg, the width of the strap is constant and the narrowing takes place on a side portion of the leg, in one of the two strands, in order to enable said strand to be inserted in the other strand that is referred to a textile frame.

Furthermore, at least a portion of the first strap 3 may be covered on its exposed surface in contact with the user's leg by a coating of damping material, so as to follow the movements of the user with limited rubbing.

The device 10 has two side cheeks 11 a and 11 b for placing on either side of the knee so as to clamp onto the femur condyles CF. The side cheeks 11 a and 11 b may themselves be in contact with the garment covering the condyles CF or they may be in contact with the condyles CF via spacers, as described below.

It can readily be understood that the co-operation between the high portion 11 of the shell 10 and the portion of the knee corresponding to the zone in which the condyles CF are present is important for the effectiveness of the device of the invention. In a preferred embodiment, the contact of the side cheeks against the condyles of the femur takes place via ergonomic spacers inserted against the inside faces of the cheeks.

The inside surfaces of the spacers may be made to measure so as to fit closely to the shape of the skier's lower limb without impeding flexion/extension movements of the knee.

The side cheeks have an outline 11 c in the form of a portion of an ellipse, having a major axis X1 oriented at an angle α of about 90° (FIG. 5A) or about 70° (FIG. 9) relative to the axis ZZ′ of the shell. This orientation α lying in the range 45° to 135° makes it possible to press in satisfactory manner against the femur condyles and thus obtain good retention of the femur in axial and sideways rotations relative to the tibia. The following embodiments show preferred orientations for the side cheeks lying in the range 70° (FIGS. 9) to 90° (FIG. 5A).

In FIG. 5A, the outline 11 c of the top and rear portions of the cheek presents a shape including substantially an upper half-ellipse and a side half-ellipse forming parts of the same virtual ellipse of center C1 that is substantially in register with the condyle CF. The major axis X1 of the ellipse is substantially perpendicular to the longitudinal main axis of the shell and perpendicular to the rectilinear section of the front face limit 10 a of the shell in a section on a longitudinal midplane of the shell. Each cheek is defined by a bottom tangent X2 of said ellipse that is substantially in register with the tibial plane X′Y′ parallel to the major axis X1 of the ellipse. The major radius R of the ellipse is 65 mm and the minor radius r of the ellipse is 50 mm. The center C1 of the ellipse is situated at a distance d=68 mm from the front face limit 10 a of the shell in a section on the longitudinal midplane of the shell. The total area of each cheek 11 a, 11 b as defined by the surface situated above the bottom tangent line X2 to the ellipse that is parallel to X1 and behind an axis Z2 parallel to the minor axis Z1 of the ellipse is situated at about ½R from the rectilinear section of the front face 10 a of the shell in section on the longitudinal midplane of the shell, and said surface area is about 100 cm².

The spacers present a contact surface against the side face of the knee of different shapes for the two opposite side faces of the knee, and more particularly an embossed shape of varying thickness less than 25 mm, and in particular lying in the range 1 mm to 25 mm.

Thus, the side cheeks completely cover the distal femoral epiphysis, each bearing on opposite sides of the end of the femur, i.e. against the femur condyles CF on either side of the knee. They serve to limit sideways rotation of the femur F relative to the foot P of the skier S.

Advantageously, the force with which the cheeks press at rest (in the absence of force due to any rotation at the knee) against the condyles is adjustable. The cheeks apply a force on the condyles substantially normal to the flanks of the thigh with a magnitude lying in the range [0, 100N].

FIGS. 8A and 8B show the spacers 30 a and 30 b constituted by a flexible lining 30-1 over a rigid support 30-2. It can be seen that the surfaces of these functional portions 30-1 of these spacers 30 are molded with very particular shapes. FIG. 5B shows a shell 10 having a single support for spacers 30 a, 30 b and a cushion 30 c useful for positioning the shell 10 relative to the leg of the skier S.

These shapes correspond to melding of the surfaces observed over the condyles CF of the femur F between two preferred positions, which may for example be the positions of extreme flexion of the thigh of the skier S as shown in FIG. 9.

This maximizes comfort for the skier who, between the two extreme positions, conserves sideways pressure that matches the skier's morphology, i.e. that is personalized, and that acts against the condyles of the femur. The functional portions 30 a and 30 b of the spacer 30 are thus not symmetrical, since the sides of the knee have shapes and deformations that are quite distinct during their flexion movements. In contrast, symmetry may exist between the corresponding functional portions for the two knees.

The spacers 30 a and 30 b define an intermediate portion of the inside surface 10 b of the shell 10 in front of the tibia, which portion may remain recessed relative to the surfaces of the portions 30 a and 30 b. Nevertheless, between the side cheeks 11 a and 11 b, formed in this example by the side spacers 30 a and 30 b of the spacers 30, the invention may include a cushion 30 c for pressing against the kneecap of the user's knee. It can be understood that the invention thus makes it possible to distinguish between modes of physical contact between the condyles CF and the shell 10 via the side cheeks 11 a and 11 b, possibly constituted by the spacers 30 a and 30 b, and the front surface of the knee via the kneecap. More precisely, it is advantageous to use a material for the cushion that is of density lower than that of the side cheeks 11 a, 11 b so as to produce support that is more flexible with damping of the forces transmitted on contact. By way of example, a cushion made of cellular material having density lying in the range 30 kg/m³ to 900 kg/m³ has given satisfaction.

In an embodiment, the surface of the cushion that comes to face the kneecap is situated in continuity with the surfaces of the portions 30 a and 30 b covering the side cheeks 11 a and 11 b. The use of a material that is sufficiently flexible enables it to comply with the shape of the kneecap when the kneecap is in contact with the cushion. The cushion also makes it possible to provide a damping function against violent impacts by damping the rearward movement of the shell assembly in the event of an impact.

Another function of the cushion is to avoid a gap persisting between the side spacers 30 a and 30 b into which snow might penetrate while performing winter sports. It should be observed that a silicone-based cellular material gives good results given the above-described density constraints and its ability to withstand large temperature variations. The same material can be used as a covering for the surface of the first strap 3 that is to come into contact with the user's leg.

FIGS. 4A and 4B and 5A to 5C show a preferred embodiment of the connection means for linking the shell to the boot. In this variant embodiment, the connection between the low portion of the shell and the cuff of the boot provided by associating the first and second connection means prevents the shell from moving in rotation relative to the boot about an axis substantially parallel to the axis of the cuff of the boot.

Still more particularly, said first and second connection means include at least one non-stretch second strap 13 a comprising two strands 13 a-1, 13 a-2 fastened to or suitable for being fastened in removable manner (23) to either side on the rear of the cuff, and two strands 13 b-1, 13 b-2 of two third straps 13 b, 13 b-1, 13-2 fastened to or suitable for being fastened in removable manner 12 a, 12 b to each side of the shell in its bottom portion, said strands of said second third straps including complementary reversible connection means at their free ends 13 c, 13 d suitable for reversibly securing the free ends 13 c of the strands 13 a-1, 13 a-2 of the second straps 13 a with the free ends 13 d of the strands 13 b-1, 13 b-2 of the third straps 13, securing the bottom portion 12 of the shell 10 to the cuff 21 of the boot 2 thus preventing the shell 10 from moving in rotation relative to the boot 2 about an axis substantially parallel to the axis ZZ′ of the shell or of the cuff 21 of the boot (2) after said second and/or third straps have been tightened by the skier.

Said second straps 13 a-1, 13 a-2 are fastened on a hook 23 fastened or suitable for fastening on the rear of the cuff 21. The third straps 13 b-1, 13 b-2 are fastened, in particular riveted, to frames or orifices O in both side edges in the bottom portion 12 of the shell 10. The free ends of the second straps 13 a-1, 13 a-2 include fastener clips 13 c suitable for co-operating to provide reversible fastening with complementary elements 13 d at the free ends of the third straps 13 ba-1, 13 ba-2.

In FIGS. 6A and 6B, in a simplified version, only one strap is used on each side that is permanently attached to the shell or to the rear of the boot. The connection means comprise only two second or third straps 13 a, 13 b secured to parts 23 of the cuff or respectively to orifices O in the shell. Under such circumstances, it is the adjustment of the straps fastened in the orifices O or on the hooks 23 that fully determines the angular sector over which the shell can pivot relative to the boot, where appropriate. Advantageously, the strap presents a particular length or a particular marking for adjustment purposes. In a variant, adjusting the straps 13 a, 13 b in slack manner or giving them pre-calibrated ability to stretch serves to limit rotation of the shell 10 relative to the boot 2, where appropriate. It can be understood that using two straps, one on each side of the boot 2 is necessary in order to limit rotation in both directions.

In another variant, shown in FIGS. 9A and 9B, the bottom portion 12 of the device 10 in this example has second connection means 12 a in the form of two notches 12 a separated by a tongue L. The second connection means 12 a of the shell are complementary to the first connection means, and given reference 22 a, acting as guide parts on the cuff 21 of the boot 2, being made up of two jaw-forming elements referenced M1 and M2. Each tongue referenced L slides between two pairs of jaws M1 and M2 placed on either side of the cuff 21. It may be observed at this point that it is possible to envisage using only one pair of jaws M1, M2 placed on only one of the sides of the cuff 21 of the boot 2, preferably on the outside. This pair of jaws associated with a tongue logically suffices to limit rotation of the shell relative to the boot providing the shell is secured elsewhere to the skier's tibia with the help of a said first strap 3 or self-gripping tape. Nevertheless, the use of two pairs enables the behavior of the shell to be made more robust and in particular makes it possible to avoid it pivoting as a whole about the tongue L. The width of the open gap between the two jaws M1 and M2 is greater than the width of the tongue L, so the tongue can move a little, with this movement leading to movement in rotation of the device 10 over a limited angular sector. Thus, fastening the device 10 on the cuff 21 of the boot 2 provides a degree of freedom in rotation relative to the boot 2 over an angular sector that is predetermined and limited. The jaws M1 and M2 may also be positioned in such a manner that the tongue is prevented from moving in rotation. Under such circumstances, the shell is maximally secured to the boot and protection of the knee is optimized.

During a movement of the femur in rotation relative to the axis of the ski, the femur comes into abutment against the side cheeks 11 a and 11 b and prevents the knee being twisted. Nevertheless, this can hinder skiability in an application to skiing.

It can thus be understood at this point that it is advantageous to use embodiments of the invention that allow a limited amplitude of rotation to be obtained. The use of a small angular sector over which the shell 10 is free to move in rotation is advantageous from a skiability point of view. Such a freedom to move in rotation over a limited angular sector does not significantly degrade the protection conferred by the invention, since the joints in question have a certain tolerance margin before being damaged.

The jaw-forming elements M1 and M2 are stationary relative to the boot 2. Nevertheless, at least one of the elements M1 and M2 could be slidably mounted in order to be able to adjust the side space in which the second connection means 12 a and 12 b of the shell can move. This thus makes it possible to adjust the angular sector over which the tongues La of the second connection means 12 a of the shell 10 can move in the first connection means 22 a fastened to the cuff 21 of the boot 2. 

1-15. (canceled)
 16. A device for protecting the knee joint of a user, the device being for installing on a ski boot, said device comprising: a single rigid shell having an inside surface suitable for covering at least in part an anterior portion of the user's leg, the shell having a top portion for being situated level with the knee and a bottom portion including connection means suitable for connecting the bottom portion of the shell to the ski boot, the top portion including side cheeks suitable for extending over side faces of the knee and at least facing the condyles of the user's femur; spacers pressed against the inside faces of said cheeks and presenting bearing surfaces suitable for fitting closely in part at least to the shapes of the sides of the knee at the level of the condyles so as to block forward movement in translation of the knee relative to the shell and so as to block movement in rotation of the knee relative to the shell, without hindering flexion movements of the lower limb; at least a first strap for attaching around a zone of the top portion of the leg below the knee at the top portion of the calf; and attachment means for attaching said first strap to the surface of the shell, including at least one intermediate piece having at least a first portion that is fastened to the inside surface of the shell and having at least one second portion that is fastened to the portion of the first strap, said attachment means allowing the inside surface of said shell to be spaced apart from the front portion of the leg at the level of an attachment zone; and said first strap, on its own or in combination with said attachment means, being suitable for surrounding and for being in contact with the leg over the entire periphery of its section.
 17. The device according to claim 16, comprising a single said first strap for attaching around the top portion of the calf, immediately below the knee joint.
 18. The device according to claim 16, wherein said intermediate piece enables spacing between the front portion of the leg and the inside surface of the shell, at the level of said attachment zone, to be adjusted in the range 3 mm to 50 mm.
 19. The device according to claim 16, wherein said attachment means is fastened to at least one attachment zone of the inside surface of the shell, said attachment means being arranged symmetrically about the middle of the width section of the shell.
 20. The device according to claim 18, wherein said attachment means includes at least a single intermediate piece having its central portion fastened to a single attachment zone of the inside surface of the shell, substantially in the middle of the section of the shell, with its two side portions having ends arranged on either side of said central portion substantially symmetrically about said connection zone being fastened to the portion of the first strap that is suitable for coming into contact with the front portion of the tibia.
 21. The device according to claim 18, wherein said first strap and said intermediate piece comprise a piece of flexible material, constituted from a flexible strip of non-stretch textile material.
 22. The device according to claim 16, wherein said first strap includes at least a first portion situated facing the inside surface of the shell and suitable for coming into contact against the anterior portion of the leg, and at least one second portion extending beyond the first portion, the width of the first portion being greater than the width of the second portion.
 23. The device according to claim 16, wherein at least a portion of the face of the first strap that is to be exposed to contact with the leg includes a covering of flexible material, of cellular material type or of gel type.
 24. The device according to claim 16, wherein said first strap has two strands that are distinct or in continuity with each other at a first end of each strand, the two strands being suitable for extending at least over two respective sides of the leg and each having a said first end fastened to said attachment means, the second free ends of the two strands being suitable for joining together over the posterior portion of the leg.
 25. The device according to claim 24, wherein said first strap includes a buckle frame of flexible material at the free end of one of the strands and/or a Velcro type self-adhesive system configured to secure the free end of the other strand on the posterior portion of the leg, said frame preferably being an orifice incorporated in the end of a first strand that is greater in width than the end of the second strand, which second strand is suitable for passing through said frame.
 26. The device according to claim 16, wherein said spacers are spacers molded to have embossed shapes complementary to the shapes of the side faces of the knee at the level of the condyles.
 27. The device according to claim 16, wherein said boot includes a cuff, and said connection means is suitable for securing the bottom portion of the shell to the cuff portion of the boot covered by the bottom portion of the shell in such a manner as to limit rotation of the shell relative to the boot about an axis that is substantially parallel to the axis ZZ′ of the shell and/or of the cuff.
 28. The device according to claim 27, wherein said connection means comprises a first connection means, suitable for being fastened to the cuff of the boot, and a second connection means complementary to the first connection means of the cuff, for securing with the cuff of the boot, said connection means preferably comprising at least one second strap and/or at least one third strap fastened to or suitable for being fastened to said shell and/or fastened to or suitable for being fastened to said cuff.
 29. The device according to claim 28, wherein said first and second connection means include at least one non-stretch second strap comprising two strands fastened to or suitable for being fastened in removable manner to either side on the rear of the cuff, and two strands of two third straps fastened to or suitable for being fastened in removable manner to each side of the shell in its bottom portion, said strands of said second third straps including complementary reversible connection means at their free ends suitable for reversibly securing the free ends of the strands of the second straps with the free ends of the strands of the third straps, securing the bottom portion of the shell to the cuff of the boot thus preventing the shell from moving in rotation relative to the boot about an axis substantially parallel to the axis (ZZ′) of the shell or of the cuff of the boot after said second and/or third straps have been tightened by the skier.
 30. Sports equipment comprising a sports boot including said first connection means and a protection device according to claim 28 having said second connection means. 